Question 841777:  Please help me solve this problems:
 
1.A circle whose centre lies on the line y=3x-1, touches both axes: 
find: 
(A) the equation of the circle 
(B) the points where the circle intersects the line 2y+x=1
 
2.Find the equation of the circle which passes through the points (0,3), (-1,2) and (7,-4)
 
3.A circle passes through the points (1,-15) and (-11,3). Its centre lies on the line 5y-12x+22=0. Find the coordinates of the centre, the radius and the equation of the circle.
 
4.The circle X^2 + Y^2 + 2x - 4y - 11 = 0 and the line X-y+1=0 intersect at A and B.Find the equation of the circle having AB as diamater.
 
 
Thank you in advance! 
Best regards, 
Kalin Mihow 
 Answer by Alan3354(69443)      (Show Source): 
You can  put this solution on YOUR website! 1.A circle whose centre lies on the line y=3x-1, touches both axes: 
find: 
(A) the equation of the circle 
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If by "touches" you mean tangent, then the center has to be on the line y = x to be equidistant from both axes. 
Find the intersection of y=3x-1 and y = x.  Call it (h,k) 
---- 
The radius of the circle is the distance, h. 
The eqn is   
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(B) the points where the circle intersects the line 2y+x=1 
Solve for the 2 points. 
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2.Find the equation of the circle which passes through the points (0,3), (-1,2) and (7,-4) 
Do you know about determinants? 
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3.A circle passes through the points (1,-15) and (-11,3). Its centre lies on the line 5y-12x+22=0. Find the coordinates of the centre, the radius and the equation of the circle. 
Try it, email via the Thank You note for help or to check your work. 
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4.The circle X^2 + Y^2 + 2x - 4y - 11 = 0 and the line X-y+1=0 intersect at A and B.  Find the equation of the circle having AB as diamater. 
Try it, email via the Thank You note for help or to check your work. 
 
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